From The Belle Jar:
We never say that all men deserve to feel beautiful. We never say that each man is beautiful in his own way. We don’t have huge campaigns aimed at young boys trying to convince them that they’re attractive, probably because we very rarely correlate a man’s worth with his appearance. The problem is that a woman’s value in this world is still very much attached to her appearance, and telling her that she should or deserves to feel beautiful does more to promote that than negate it. Telling women that they “deserve” to feel pretty plays right in to the idea that prettiness should be important to them. And having books and movies aimed at young women where every female protagonist turns out to be beautiful (whereas many of the antagonists are described in much less flattering terms) reinforces the message that beauty has some kind of morality attached to it, and that all heroines are somehow pretty.